Insulation

ABSTRACT

Insulation sheeting ( 10 ) comprising two outer layers ( 11, 12 ) and a closed cell structure ( 13 ) bonded therebetween. The sheeting ( 10 ) is of a thickness which allows it to be disposed in a rolled configuration and also unrolled to assume a substantially flat configuration. The outer layers ( 11, 12 ) each comprises reinforced reflective aluminium foil. The closed cell foam structure ( 13 ) comprises flexible light gauge foam such as cross-linked LDPE foam. The outer surface of one of the layers ( 11, 12 ) is treated to provide some glare reduction while retaining heat reflective characteristics. Because of the closed cell structure ( 13 ), the insulation sheeting ( 10 ) can compress under load for fixing while still affording worthwhile insulation benefits. For certain applications, the insulation sheeting ( 10 ) may be perforated for air and water vapour permeability.

BACKGROUND

1. Field of the Invention

Example embodiments in general relate to insulation, and moreparticularly insulation sheeting.

2. Description of the Art

There are various types of insulation currently available for buildings,including thermo-reflective insulating sheeting. An example ofthermo-reflective insulation sheeting is disclosed in the Applicant'sAustralian Innovation patent 2003100663. Such insulating sheetingcomprises a single layer closed cell structure interposed between twoouter layers, at least one of which comprises reflective foil. Thisinsulation sheeting has proved to be a particularly effective barrier inreducing energy transfer, the closed cell structure serving to reducethe amount of heat transferred through convection and conduction, andthe reflective foil layer serving to reduce heat transfer throughradiation.

The single layer closed cell structure comprises a plurality of plasticmembranes bonded together to form a plurality of air cells therebetween.The air cells are of generally cylindrical construction each of adiameter between eight millimetres and twenty five millimetres, and adepth of between about three millimetres and ten millimetres.

The dimensions of the air cells were selected to provide the necessaryinsulation characteristics without the need to rely upon a double layercell structure which was previously used in the prior art.

However, insulation sheeting comprising a single layer cell structuredefined by membranes bonded together may have some limitations.

SUMMARY

An example embodiment of the present invention is directed to aninsulation sheeting comprising a cell structure interposed between twoouter layers, the cell structure comprising a closed cell foamstructure.

In an example, the closed cell foam structure is flexible andresiliently compressible.

In an example, the closed cell foam structure comprises polyethylenefoam. More preferably, the closed cell foam structure comprisescross-linked low density polyethylene (LDPE) foam.

The foam structure can provide resistance to moisture absorption andthereby enhances resistance to development of mould.

The LDPE foam can provide the insulation sheeting with enhanced thermaland acoustic insulation characteristics as well as greater resistance toheat and flame.

In an example, at least one of the two outer layers comprises reflectivefoil. More preferably, both outer layers comprise reflective foil.

In an example, the reflective foil comprises aluminium foil. Thealuminium foil may comprise 99.5 percent pure aluminium reflective foil.

In an example, at least one of the outer layers is reinforced for tearresistance. The reinforcement may be provided by a scrim bonded to thefoil layer for reinforcement to provide strength and tear resistance. Inan example, the scrim comprises high density polyethylene weavelaminated to the aluminium foil. Other types of scrim can also be used,one example being polypropylene weave.

In an example, one of the reflective layers may be treated for glarereduction. The layer may be treated in any appropriate way, such as byapplying a surface treatment such as colouring thereto. Suitable coloursfor the surface treatment comprise red, blue, green or orange tones.

The treatment for glare reduction is designed to provide a reduction ofglare to provide greater comfort and protection against glare blindnesswhile still providing a low enough emittance to provide thermalresistance by way of an upper reflective air space ideally within arange of E=0.08 to E=0.14

The close cell foam structure can be provided with fire retardency. Thismay be achieved by the addition of an appropriate quantity of a fireretardant substance to the resin from which the foam structure isformed.

In an example, antioxidant is added to the foam to provide durability.Preferably, UV protection is also provided to the insulation sheeting.

The insulation sheeting can compress under load for fixing while stillaffording worthwhile insulation benefits. This is because of thepresence of the closed cell foam structure.

For certain applications, the outer layers may be perforated for air andwater vapour permeability through the insulation sheeting.

In an example, the perforations are of a size, spacing and number toprovide permeability to water vapour in accordance with achieving a lowclassification for resistance to water vapour transmission underAustralian and New Zealand standard AS/NZS4200.1. Such permeability willallow the building to “breath” through the insulation sheeting and alsominimises the build up of condensation attributable to the barriereffect of the insulation sheeting.

In an example, the perforations are formed after construction of theinsulation sheeting. In one arrangement, the perforations may extend notonly through the two outer layers but also entirely through the closedcell foam structure located therebetween. In another arrangement, theperforations may extend through the two outer layers and partly throughthe closed cell foam structure located there between. In the latterarrangement, the perforations may extend into the closed cell foamstructure from one outer layer and terminate within the closed cell foamstructure inwardly of the other outer layer. With this arrangement, theperforations may comprise holes extending though said one outer layerand into the closed cell foam structure to terminate inwardly of theother outer layer, the holes opening onto said one outer layer atopenings therein and there being corresponding opening is the otherouter layer.

The perforations in the outer layers and the central closed cell foamstructure can be in alignment to assist air and moisture vapourtransmission through the sheeting. The perforations may be generated byperforating the sheeting with a perforating device comprising a set ofsharp end extrusions designed to perforate the sheeting at a variety ofpredetermined intervals.

Another example embodiment is directed to a building constructioncomprising a frame, cladding attached to the frame, and insulationbetween the frame and the cladding. The insulation includes insulationsheeting having a cell structure interposed between two outer layers,where the cell structure includes a closed cell foam structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by reference to the followingdescription of several specific embodiments thereof as shown in theaccompanying drawings.

FIG. 1 is a schematic fragmentary elevational view of insulationsheeting according to a first embodiment, with part of an outer layer ofthe sheeting removed to reveal the inner closed cell foam structure.

FIG. 2 is a fragmentary side elevational view of the insulation sheetingof FIG. 1.

FIG. 3 is a fragmentary perspective view of a building construction inwhich insulation sheeting according to the first embodiment isinstalled.

FIG. 4 is a fragmentary sectional view of the building constructionshown in FIG. 3.

FIG. 5 is a schematic fragmentary elevational view of insulationsheeting according to a second embodiment, with part of an outer layerof the sheeting removed to reveal the inner closed cell foam structure.

FIG. 6 is a fragmentary side elevational view of the insulation sheetingof FIG. 5.

FIG. 7 is a fragmentary side elevational view of insulation sheetingaccording to a third embodiment.

DETAILED DESCRIPTION

Example embodiments of the invention have been devised particularly,although not necessarily solely, for insulating buildings and otherstructures. Accordingly, the embodiments also relate to a buildingconstruction incorporating the insulating sheeting.

Referring to FIGS. 1 and 2 of the drawings, there is shown insulationsheeting 10 according to the first embodiment. The insulation sheeting10 comprises two outer layers 11, 12 and a closed cell structure 13bonded therebetween. Each outer layer 11, 12 has an outer surface 14.

The sheeting 10 is of a thickness between the outer surfaces 14 whichallows the sheeting to be disposed in a rolled configuration and alsounrolled to assume a substantially flat configuration. The thickness canbe up to about 12 mm for typical applications. In one typicalapplication the thickness is about 4 mm and in another typicalapplication it is about 8-9 mm.

The outer layers 11, 12 each comprises reinforced reflective aluminiumfoil. The reflective aluminium foil comprises 99.5% pure aluminiumreflective foil reinforced with high density polyethylene scrim. Thereinforcement enhances the tensile strength of the insulation sheeting10, allowing it to be installed over large spans in a buildingconstruction. The reinforcement also provides greater tear strength.

The outer layers 11, 12 can be applied to the closed cell foam structurein any appropriate way. One particularly suitable way involves a hotmelt lamination process.

The closed cell foam structure 13 comprises flexible light gauge foamwhich is compressible with at least some resiliency. In this embodiment,the closed cell foam structure 13 comprises cross-linked LDPE foam. Thepolyethylene foam incorporates UV protection, fire retardancy and anantioxidant. The fire retardancy is such as to provide compliance withAS1530.2. Indeed, the fire retardant may provide a Fire Index of lessthan or equal to five under AS1530.2. Antioxidant protection is such asto afford a minimum 15 year product life when installed.

The cross-linked structure of the closed cell foam structure 13 providesenhanced thermal and acoustic insulation characteristics, as well asgreater resistance to heat and flame, in comparison to the prior artinsulation sheeting referred to previously. Specifically the closed cellfoam structure 13 produced from cross-linked LDPE foam allowsconstruction of insulation sheeting which is thinner than the prior artsheeting referred to previously because of inherent stiffness in thefoam arising from the cross-linking. Further, the closed cells withinthe cross-linked LDPE foam are much smaller in size than the air cellsin the prior art sheeting. Indeed, the closed cells in the foamstructure 13 comprise micro-encapsulated air cells, typically of across-sectional size less than 0.1 mm. With this arrangement, the aircells are generally evenly distributed within the foam structure 13, soaffording better fire resistance. This is because there are norelatively large bubbles of air to support combustion, as exist in theprior art insulation referred to previously. The even distribution ofmicro-encapsulated air cells also provides resistance to thermal andacoustic energy transfer.

In this embodiment, the reflective foil has a thickness of about 6.5 μmand the scrim comprises high density polyethylene scrim with a 6 mm by 6mm weave.

The outer surface 14 of one of the layers 11, 12 is treated to providesome glare reduction while retaining heat reflective characteristics.Glare reduction can be particularly desirable on construction siteswhere the sheeting may be exposed for some time so creating a glareproblem for persons in the vicinity. In this embodiment, the treatmentcomprises colouring. In this embodiment, the colouring comprises anorange pigment.

The insulating sheeting according to the first embodiment has a materialthermal resistance of R0.20m2K/W (+/−0.25 m2K/W).

In addition to providing a barrier to heat transfer, the sheeting 10according to the first embodiment also provides a barrier to air andwater vapour.

The insulation sheeting 10 can compress under load for fixing whilestill affording worthwhile insulation benefits. This is because of thepresence of the closed cell foam structure.

The insulation sheeting is suitable for use in building constructioninvolving a frame and cladding attached to the frame, where theinsulation sheeting can be installed between the frame and the cladding.The cladding may comprise wall cladding or roof cladding.

The insulation sheeting is particularly suitable for installation steelframe building construction, where it may be necessary to a thermalbreak between the steel framing and the wall cladding to reduce thermalbridging and conductivity the framing and the cladding. A typicalexample of such an installation is shown in FIGS. 3 and 4. Theinstallations comprise the sheeting 10 installed between a wall frame 15and cladding 16 of a building construction 17. The wall frame 15comprises wall frame elements such as studs 18 and noggings 19. Thecladding 16 is attached to the wall frame 15 at appropriate locations20, with the insulation sheeting 10 compressed there between. Spacers 21(known as spacer biscuits) provided on the insulation sheeting 10 tomaintain the insulation sheeting in spaced apart relation to thecladding 16 to establish a gap 23 there between (other than at locationswhere the insulation sheeting 10 is compressed between the cladding 16and the wall frame elements).

The insulation sheeting according to this embodiment can function as athermal break, insulation and vapour barrier. It is waterproof andunaffected by water in normal applications. Accordingly, it is suitablefor humid climates and can afford protection against water damage. Itwill not promote growth of fungi or bacteria and does not provide anesting medium for rodents and insects.

There are certain situations where it is desirable that insulationsheeting have some permeability to air and water vapour so as to reducethe risk of moisture damage due to condensation. The insulation sheetingaccording to a second embodiment seeks to provide such insulationsheeting.

Referring now to FIGS. 5 and 6, the insulation sheeting according to thesecond embodiment is similar in many respects to the insulation sheetingaccording to the first embodiment and so corresponding referencenumerals are used to identify corresponding parts.

In the second embodiment, however, the insulation sheeting is providedwith permeability to air and water vapour. In this regard, theinsulation sheeting has a plurality of perforations 25 extending throughthe sheeting 10 between the two outer surfaces 14. The perforations 25comprise holes 27 formed by piercing the sheeting 10 with a perforatingtool. The holes 27 not only extend through the outer layers 11, 12 toopen on to the outer surface 14 thereof at openings 28 but also extendthrough the closed cell foam structure 13. The perforations 25 are notapparent in the closed cell foam structure 13 owing to the compressiblenature of the foam. Even though collapsed within the closed cell foamstructure 13, the perforations 25 do provide a transmission path throughthe sheeting 10 for air and water vapour.

Referring now to FIG. 7, the insulation sheeting according to the thirdembodiment is similar in many respects to the insulation sheetingaccording to the second embodiment and so corresponding referencenumerals are used to identify corresponding parts.

In the third embodiment, the perforations 25 extend through the twoouter layers 11, 12 and partly through the closed cell foam structure 13located there between. More particularly, the perforations compriseholes 27 which extend into the closed cell foam structure 13 from outerlayer 11 and terminate within the closed cell foam structure inwardly ofthe other outer layer 12. The perforations comprise openings 28 in thetwo outer layers 11, 12 as was the case with the second embodiment. Theholes 27 extend from corresponding openings 28 in outer layer 11 andterminate inwardly of openings 28 in outer layer 12 to define spaces 29there between.

It should be appreciated that the scope of the invention is not limitedto the scope of the three embodiments described. For example, it is notnecessary that both outer layers 11, 12 be reflective foil. One of theouter layers could be reflective foil (treated for glare reduction) andthe other layer could comprise a membrane of any appropriate typeincluding for example polyethylene film.

Modifications and changes can be made without departing from the scopeof the invention.

Throughout the specification, unless the context requires otherwise, theword “comprise” or variations such as “comprises” or “comprising”, willbe understood to imply the inclusion of a stated integer or group ofintegers but not the exclusion of any other integer or group ofintegers.

1. Insulation sheeting, comprising: a pair of outer layers, and a cellstructure interposed between the outer layers, wherein the cellstructure includes a closed cell foam structure.
 2. The insulationsheeting according to claim 1, wherein the closed cell foam structure iscomposed of a polyethylene foam.
 3. The insulation sheeting according toclaim 2, wherein the closed cell foam structure is composed of across-linked low density polyethylene (LDPE) foam.
 4. The insulationsheeting according to claim 1, wherein at least one of the two outerlayers includes a reflective layer.
 5. The insulation sheeting accordingto claim 4, wherein both outer layers include a reflective layer.
 6. Theinsulation sheeting according to claim 5, wherein the reflective foilcomprises aluminum foil.
 7. The insulation sheeting according to claim6, wherein the aluminum foil comprises 99.5 percent pure aluminumreflective foil.
 8. The insulation sheeting according to claim 1,wherein at least one of the outer layers is reinforced for tearresistance.
 9. The insulation sheeting according to claim 8, wherein thereinforcement includes a scrim bonded to the outer layer.
 10. Theinsulation sheeting according to claim 9, wherein the scrim is a highdensity polyethylene weave that is laminated to the outer layer.
 11. Theinsulation sheeting according to claim 4, wherein at least one of thereflective layers is treated for glare reduction.
 12. The insulationsheeting according to claim 1, wherein the closed cell foam structure isprovided with fire retardant properties.
 13. The insulation sheetingaccording to claim 1, wherein the closed cell foam structureincorporates an antioxidant for durability.
 14. The insulation sheetingaccording to claim 1, wherein the closed cell foam structure has UVprotection.
 15. The insulation sheeting according to claim 1, whereinthe outer layers are perforated for air and water vapor permeabilitythere through.
 16. The insulation sheeting according to claim 15,wherein the perforations are formed after construction of the insulationsheeting.
 17. The insulation sheeting according to claim 15, wherein theperforations extend through the two outer layers and the closed cellfoam structure located therebetween.
 18. The insulation sheetingaccording to claim 15, wherein the perforations include holes extendingthough one outer layer and into the closed cell foam structure toterminate inwardly of the other outer layer.
 19. The insulation sheetingaccording to claim 18, wherein the holes open onto the one outer layerat openings therein, and there are corresponding openings in the otherouter layer.
 20. The insulation sheeting according to claim 17 whereinthe perforations in the outer layers and closed cell foam structure arein alignment to assist air and moisture vapor transmission through thesheeting.
 21. A building construction, comprising: a frame, claddingattached to the frame, and insulation between the frame and thecladding, the insulation including insulation sheeting composed of apair of outer layers and a cell structure interposed between the outerlayers, wherein the cell structure includes a closed cell foamstructure.
 22. (canceled)